The terminal compliance date for highway diesel fuel is September 1, 2006 (as amended by the November 22, 2005 technical amendments to the rulemaking) for all fuel they designate as 15 ppm diesel fuel.
Question and Answer was originally posted at Questions and Answers on the Clean Diesel Fuel Rules (PDF)(135 pp, 888 K, EPA420-B-06-010, July 2006, About PDF)